Miscellaneous Intelligence. 319 



together with some member of the spinel group. These occur- 

 rences are divided into three groups. In the first, the ferruginous 

 group, the pyroxene is a highly ferriferous enstatite and the spinel 

 either hercynite, or hercynite with magnetite ; in this group 

 ilmenite may largely replace the corundum. In the second, the 

 ferro-magnesian group, ferrous oxide is largely replaced by mag- 

 nesia, a less ferriferous enstatite and pleonaste, also sometimes 

 chrysolite, being the type minerals. In the third, or magnesian 

 group/ iron compounds occur in very small quantity, the associ- 

 ated minerals being magnesian forms of chrysolite, also (secondary) 

 talc, dolomite, magnesite. 



In the second class, the corundum is associated with acid 

 rocks. This is well illustrated by the sapphire of Kashmir, which 

 occurs in granite ; here the granite (pegmatite) forms veins in 

 gneiss and carries with the sapphire, tourmaline, euclase, cyanite, 

 etc. ; green tourmaline, spodumene, cookeite and prehnite are 

 also found. The gneiss is coarse and schistose, with white feldspar, 

 black mica and also garnets. 



The corundum of Ontario, as described by Mr. Miller, belongs 

 chiefly to dikes of syenite and quartz pegmatite intersecting the 

 Laurentian gneiss. It is found more abundantly in ordinary 

 syenite than in nepheline syenite, but in the latter the crystals 

 are better formed. It is also found in eastern Ontario in crys- 

 talline limestone, as in Burma, where it is regarded as of second- 

 ary origin. Mr. Miller's paper is accompanied by numerous 

 interesting plates illustrating the actual occurrence of the min- 

 eral. Other mineralogical points are also brought out, as the 

 occurrence of nickel-bearing magnetite, also of a mineral of the 

 columbite type (G. = 5'40), in -Renfrew County. 



11. Minerals in Rock Sections : The practical methods of iden- 

 tifying minerals in rock sections with the microscope. Especially 

 arranged for students in technical and scientific schools. By Lea 

 McIlvaine Luquer; pp. 117. New York, 1898 (D. Van 

 Nostrand Company). — This subject has been already treated of 

 by a number of authors, but there still remains place for the 

 present volume. It gives in the opening chapters a concise sum- 

 mary of the optical principles, methods and instruments, and 

 following a statement of the characters of minerals arranged with 

 system and clearness, A chapter is also added on the methods of 

 making sections and one on chemical tests. An optical scheme 

 is added in the appendix. 



12. New Mineral Names. — Lagoriolite. In connection with 

 his important work in mineral synthesis and the crystallization of 

 minerals from a molten magma, Morozewicz has obtained iso- 

 metric crystals or crystalline grains of a mineral having the 

 composition (Na 2 Ca) 3 Al 2 (Si0 4 ) 3 , in which Na 2 : Ca = 3 : 2. This 

 corresponds to a sodium-grossularite, a type of garnet not yet 

 noted in nature but which has peculiar interest as connecting the 

 garnets with the minerals of the Sodalite Group. This compound 

 is named after Prof. A. Lagorio. — Min. petr. Mitth., xviii, 147, 

 1898. 



